This invention relates to floating seals for fluidic devices and, particularly, to pneumatic actuators having a diaphragm forming the seal between the actuator housing and the air chamber.
Many prior art diaphragm devices have taken advantage of their existing diaphragms to seal in the fluid to which the diaphragms are responsive. The seals are provided by compressing the bead around the circumference of the diaphragm against the device housing to insure that the fluid being sealed into the fluid chamber defined by the diaphragm cannot escape from the housing around the bead. This compression is applied to the bead either by tightening a nut which presses the bead against the housing or by using a spring or other suitable biasing means to press the bead against the housing. Because a mechanism is required to compress the bead against the device housing in these prior art devices, assembly of such devices has proven to be more complicated and costly than necessary. The present invention reduces the complexity and cost of assembly of the device by dispensing with the compressing mechanism and rather compressing the bead against the housing by use of the fluid which is supplied to the fluidic device. In this arrangement, the diaphragm and the bead of the diaphragm are allowed to float in the housing when no fluid is supplied to the device.